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Date:      Mon, 22 Jun 2026 17:02:40 +0000
From:      bugzilla-noreply@freebsd.org
To:        bugs@FreeBSD.org
Subject:   [Bug 296208] gpart(8): Backup/Create/Restore Differences
Message-ID:  <bug-296208-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=296208

            Bug ID: 296208
           Summary: gpart(8): Backup/Create/Restore Differences
           Product: Base System
           Version: 15.1-RELEASE
          Hardware: Any
                OS: Any
            Status: New
          Severity: Affects Many People
          Priority: ---
         Component: bin
          Assignee: bugs@FreeBSD.org
          Reporter: vermaden@interia.pl

Hi,

the gpart(8) command is not able to identically recreate the partition table
with 'backup|restore' pipe.



TL;DR This is how it looks after this command:

# gpart backup md0 | gpart restore md1      

# gpart show md0                      
=>     40  2097072  md0  GPT  (1G)
       40     1024    1  freebsd-boot  (512K)
     1064    81920    2  efi  (40M)
    82984  2014128    3  freebsd-zfs  (983M)

# gpart show md1
=>     34  2097085  md1  GPT  (1G)
       34        6       - free -  (3K)
       40     1024    1  freebsd-boot  (512K)
     1064    81920    2  efi  (40M)
    82984  2014128    3  freebsd-zfs  (983M)
  2097112        7       - free -  (4K)



... or gpart(8) does not align against 4K with 'backup|restore' pipe because
this is how these partitions were made:

# gpart create -s GPT /dev/md0
md0 created

# gpart add -a 4k -s 512K -t freebsd-boot -l gptboot0 md0
md0p1 added

# gpart add -a 4k -s  40M -t efi          -l efiboot0 md0
md0p2 added

# gpart add -a 4k         -t freebsd-zfs  -l     zfs0 md0
md0p3 added



This is the workaround I was able to implement:

# dd < /dev/md0 > /dev/md1 bs=512 count=10
10+0 records in
10+0 records out
5120 bytes transferred in 0.007566 secs (676728 bytes/sec)

# gpart show md0                          
=>     40  2097072  md0  GPT  (1G)
       40     1024    1  freebsd-boot  (512K)
     1064    81920    2  efi  (40M)
    82984  2014128    3  freebsd-zfs  (983M)

# gpart show md1
=>     40  2097072  md1  GPT  (1G) [CORRUPT]
       40     1024    1  freebsd-boot  (512K)
     1064    81920    2  efi  (40M)
    82984  2014128    3  freebsd-zfs  (983M)

# gpart recover md1
md1 recovered

# gpart show md1   
=>     40  2097072  md1  GPT  (1G)
       40     1024    1  freebsd-boot  (512K)
     1064    81920    2  efi  (40M)
    82984  2014128    3  freebsd-zfs  (983M)



Hope that helps.

Regards,
vermaden

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